U. S. Pat. No. 4,314,648 issued Feb. 9, 1982 and assigned to the assignee of this invention discloses a gravity feed shelf in which low friction tracks are utilized and which are formed by an extrusion process and which are homogenous in nature with low friction material impregnated therein.
U. S. Pat. No. 4,470,943 issued Sept. 11, 1984 and owned by the assignee of this invention discloses and claims a process for forming a low friction plastic track which is homogenous from a mixture of high impact polystyrene and organo polysiloxane fluid such as dimethyl, diethyl and phenylmethyl siloxane and related copolymers.
U. S. Pat. No. 4,496,037 issued Jan. 29, 1985 and owned by the assignee of this invention discloses an L-shaped track component having a frangible notch along the length of the track whereby the width of the track may be reduced by severing a portion of the track base along the frangible notch.
U. S. Pat. No. 4,565,725 issued Jan. 21, 1986 and owned by the assignee of this invention discloses a composite plastic track and method of making by a coextrusion process.